JP2005299521A - Pump unit with reverse flow prevention device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need of a long pipe joint connecting a pump to a reverse flow prevention device while suppressing the lowering of the lift performance of the pump. <P>SOLUTION: This pump unit 1 comprises the pump 10 and a check valve unit 20 preventing the reverse flow of the pump 10. The check valve unit 20 is connected between the flange 15 of a pump casing 13 and a mating flange 17. The check valve unit 20 comprises a roughly cylindrical valve box 21, an inner tube 25 coaxially installed in the valve box 21, a valve element 22 formed of a cover-like material covering the top end opening of the inner tube 25, and a support member 23 openably supporting the valve element 22 so that the valve element is positioned parallel with the flow direction of water when the valve element is opened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pump unit including a backflow prevention device.

  2. Description of the Related Art Conventionally, a pump unit in which a backflow prevention device is provided in a pump discharge section or a discharge pipe in order to prevent backflow to the pump is known (see, for example, Patent Documents 1 and 2).

  Patent Document 1 discloses a check valve including a ball-type valve body as a backflow prevention device for a pump unit. This check valve includes a valve casing that houses a ball-type valve body, and the valve casing is connected to a discharge pipe. Inside the valve casing, in addition to the circulation space along the longitudinal direction of the discharge pipe (that is, the direction of water flow), there is a retreat space for retracting the ball type valve body to the side of the circulation space when the valve is opened. Is formed. In the check valve, when the pump is stopped, the ball-type valve body prevents the flow path and prevents the back flow of water. On the other hand, during the pump operation, the ball-type valve element is pushed from the flow space into the retreat space by the momentum of the discharged water, and the flow path of the discharged water is secured.

Patent Document 2 discloses a non-return packing arranged as a pump unit backflow prevention device so as to cover the discharge port of the pump. This non-return packing is formed of an elastic thin plate such as rubber and has a plurality of tongue pieces divided by radial cuts. On the reverse side of the check packing (pump outlet side), a plurality of casings are provided so as to cross the pump outlet. The tongue piece of the non-return packing is supported by the housing and is allowed to deform in the discharge direction, but is prevented from being deformed in the direction opposite to the discharge direction (back flow direction). In the non-return packing, when the pump is operated, each tongue piece is opened in the discharge direction by the momentum of the discharged water, and the flow path of the water is secured. On the other hand, when the operation of the pump is stopped, the tongues are closed to close the water flow path, thereby preventing backflow.
JP-A-11-132181 JP 2002-276484 A

  However, in the check valve disclosed in Patent Document 1, the diameter of the ball-type valve body must be larger than the inner diameter of the discharge pipe because the ball-type valve body closes the flow path of the discharge pipe. The evacuation space must be a space large enough to accommodate the ball type valve element. Therefore, as shown in FIG. 17, the valve casing of the check valve 101 is considerably larger than the discharge pipe 102. Therefore, since a large installation space is required, the check valve 101 cannot be arranged side by side with the pump 103. Therefore, the check valve 101 must be provided at a position higher than the pump 103, and a long pipe joint 105 is necessary to connect the discharge portion 104 of the pump 103 and the check valve 101. Therefore, the cost increase of the pump unit is inevitable. On the other hand, if the size of the check valve 101 is reduced without changing the structure of the check valve 101 in order to arrange the check valve 101 next to the pump 103, the pressure loss in the check valve 101 becomes excessive, and the pump 103 is not designed. Will significantly hinder the pumping performance.

  On the other hand, the non-return packing disclosed in Patent Document 2 is directly connected to the discharge part of the pump, and is arranged beside the pump. Therefore, a long pipe joint is not necessary. However, the check packing has a problem that the pressure loss is large. That is, with this non-return packing, the flow path of water is secured by curving tongue pieces made of rubber or the like to the discharge side during pump operation. However, there is a limit to the deformation due to bending, and therefore the actual flow path area in the check packing is considerably smaller than the flow path area of the discharge pipe. Also, the momentum of the discharged water has been weakened by the elastic restoring force of the tongue. Furthermore, the check packing requires a casing to prevent the tongue from opening in the reverse direction (the direction in which water in the discharge pipe flows back to the pump). Has been increasing. Therefore, in the backflow prevention device using the non-return packing, the pumping performance of the pump is considerably reduced.

  This invention is made | formed in view of this point, The place made into the objective is to make a long pipe joint unnecessary, suppressing the fall of the pumping performance of a pump.

  A pump unit according to the present invention is a pump unit including a pump having a pump casing in which a suction port and a discharge port are formed, and a backflow prevention device for preventing backflow to the pump, wherein the backflow prevention device includes: A substantially cylindrical valve casing having an inflow port formed at one end and an outflow port formed at the other end; and a valve body formed of a lid-like member that covers the flow path of the valve casing in the valve casing so as to be openable and closable. The valve body is opened and closed between an open state in which the valve body is in a posture substantially parallel to the axial direction of the valve casing and a closed state in which the valve body is in a posture orthogonal to or oblique to the axial direction of the valve casing. And a support mechanism that freely supports the shaft, and is disposed on the side of the pump at a height position below the uppermost end of the pump.

  According to the pump unit, since the backflow prevention device is disposed on the side of the pump, it is not necessary to provide a long pipe joint for connecting the backflow prevention device and the pump. That is, the pipe joint can be shortened. Alternatively, the pipe joint can be omitted. On the other hand, since the size of the backflow prevention device is reduced as the backflow prevention device is arranged on the side of the pump, there is a concern about pressure loss of the fluid. However, in the above-described backflow prevention device, the valve body is opened during the pump operation, and the valve body takes a posture substantially parallel to the axial direction of the valve casing, that is, the fluid flow direction. Therefore, the fluid flow is less disturbed by the valve body. As a result, the pressure loss of the fluid in the backflow prevention device is reduced. Therefore, a long pipe joint is not required without causing a significant decrease in the pumping performance of the pump.

  The valve casing is preferably located inside the outer edge of the pump casing in plan view.

  This promotes space saving of the pump unit. Moreover, since the valve casing does not protrude to the side, the handleability of the pump unit is improved.

  The valve casing is preferably connected directly to the pump casing.

  As a result, a pipe joint for connecting the backflow prevention device and the pump becomes unnecessary, and the number of parts can be reduced.

  A flange formed with a bolt hole is provided around the discharge port of the pump casing, and the pump is designed so that the bolt hole is formed and bolted to the flange, and a discharge pipe is connected to the pump casing. The backflow prevention device is installed between the phase flange and the flange of the pump casing by fastening the phase flange, the valve casing, and the flange of the pump casing with a common bolt. It is preferable that

  This eliminates the need to separately connect the backflow prevention device to the phase flange and the flange of the pump casing, and eliminates the need to separately provide a connecting tool for connecting them. Therefore, it is possible to reduce the cost by reducing the number of parts. Further, the connection work is simplified.

  The valve casing is provided with a substantially cylindrical inner cylinder having one end forming the inlet or continuing to the inlet and the other end opening in the valve casing. The other end side of the cylinder is opened and closed freely, and the valve casing is provided with an air vent passage that communicates the outside of the valve casing and the inside of the inner cylinder, and an air vent valve that opens and closes the air vent path. It is preferable.

  As a result, an air vent valve is built in the backflow prevention device, and there is no need to newly provide a separate air vent valve for the backflow prevention device. Moreover, it is not necessary to install an air vent valve in the discharge pipe. Therefore, it is possible to reduce the number of parts and the installation space.

  An air vent hole is formed through the side wall of the inner cylinder, and the valve casing is formed with an air discharge port that protrudes to the side of the valve casing and is open to the outside, and defines the air vent passage. An auxiliary casing is provided, and the air vent valve is movably provided in the auxiliary casing, and closes the air discharge port when fluid flows in the inner cylinder, and the air when the fluid does not flow in the inner cylinder. You may provide the ball-type valve body which opens a discharge port.

  This provides a suitable backflow prevention device with a built-in air vent valve.

  It is preferable that the auxiliary casing protrudes toward the pump and is located on the inner side of the outer edge of the pump casing in a plan view.

  This prevents the auxiliary casing from protruding sideways beyond the pump casing in plan view. Therefore, space saving of the pump unit is promoted, and handling properties are improved.

  According to the present invention, since the backflow prevention device is disposed on the side of the pump, a long pipe joint for connecting the backflow prevention device and the pump becomes unnecessary. Therefore, the cost can be reduced by reducing the number of parts. Since the valve body of the backflow prevention device is made of a lid-like member and takes a posture substantially parallel to the flow direction when opened, fluid disturbance due to the valve body can be suppressed, and pressure loss in the backflow prevention device can be kept small. it can. Therefore, it is possible to eliminate the need for a long pipe joint while suppressing a decrease in pumping performance of the pump.

  If the valve casing is arranged inside the outer edge of the pump casing in plan view, space saving of the pump unit can be promoted, and handleability can be improved.

  If the valve casing is directly connected to the pump casing, a pipe joint for connecting the backflow prevention device and the pump can be eliminated, and the number of parts can be reduced.

  If the phase flange, the valve casing, and the flange of the pump casing are fastened with a common bolt, and the backflow prevention device is installed between the phase flange and the flange of the pump casing, the backflow prevention It is not necessary to separately connect the apparatus to the phase flange and the flange of the pump casing, and the number of connectors can be reduced. In addition, connection work can be simplified.

  A substantially cylindrical inner cylinder is provided inside the valve casing, the valve body is formed so as to cover the other end side of the inner cylinder so as to be openable and closable, and the valve casing includes an exterior of the valve casing and an inner cylinder. If an air vent passage that communicates with the interior and an air vent valve that opens and closes the air vent passage are provided, it is not necessary to provide an air vent valve separately, and the number of components and the installation space can be reduced.

  A ball-type valve body that protrudes to the side of the valve casing and has an air discharge port that is open to the outside and that defines an air vent passage and that opens and closes the air vent hole in the auxiliary casing. If this is provided, the suitable backflow prevention apparatus which incorporated the air vent valve can be obtained.

  If the auxiliary casing protrudes toward the pump and is positioned on the inner side of the outer edge of the pump casing in a plan view, the space of the pump unit can be saved and the handleability can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
As shown in FIGS. 1 and 2, the pump unit 1 according to the first embodiment includes a submersible pump 10 and a check valve unit 20. FIG. 3 shows the submersible pump 10 in a state before the check valve unit 20 is mounted. That is, it represents the original configuration of the submersible pump 10. First, the configuration of the submersible pump 10 will be described with reference to FIG.

  The submersible pump 10 includes a motor casing 14, a motor (not shown) housed in the motor casing 14, an impeller (not shown) connected to a rotation shaft (not shown) of the motor, And a pump casing 13 covering the impeller. The impeller is provided below the motor, and the pump casing 13 is provided below the motor casing 14. A plurality of legs 40 are formed in the lower part of the pump casing 13, and a certain amount of gap is provided between the pump casing 13 and the ground. A suction port 11 that opens downward is formed at the center of the lower surface of the pump casing 13. A discharge port 12 that opens upward is formed on the side of the pump casing 13.

  The peripheral part of the discharge port 12 in the pump casing 13 is formed in a shape that rises upward, and constitutes a flange 15 that is substantially rhombus (see FIG. 2) in plan view. Bolt holes (not shown) through which the bolts 16 are inserted are formed in the flange 15. A companion flange 17 is provided above the flange 15. The companion flange 17 is designed to be bolted to the flange 15 and is formed in a shape corresponding to the shape of the flange 15. In the present embodiment, since the flange 15 is formed in a substantially diamond shape in plan view, the companion flange 17 is also formed in a substantially diamond shape in plan view (see FIG. 2). Bolt holes 39 (not shown in FIG. 3; see FIG. 9) through which the bolts 16 are inserted are also formed in the phase flange 17. The companion flange 17 is disposed opposite to the flange 15 and is fastened to the flange 15 by a bolt 16.

  The above is the configuration of the submersible pump 10. Next, the configuration of the check valve unit 20 will be described.

  As shown in FIG. 1, the check valve unit 20 is installed between the companion flange 17 and the flange 15 of the pump casing 13. Although details will be described later, a bolt hole 27 (not shown in FIG. 1, see FIG. 5) through which the bolt 16 is inserted is also formed in the check valve unit 20, and the check valve unit 20 includes the common bolt 16. Are fastened to the companion flange 17 and the flange 15. As shown in FIG. 4, the check valve unit 20 includes a valve box 21, a valve body 22 disposed in the valve box 21, a support member 23 that supports the valve body 22 so that it can be opened and closed, and an upper lid 24. I have.

  The valve box 21 is formed in a shape corresponding to the flange 15 and the companion flange 17 of the pump casing 13, that is, a substantially cylindrical shape having a substantially rhombic shape in plan view. As shown in FIG. 5, an inner cylinder 25 is formed in the lower central portion of the valve box 21. Therefore, a part of the check valve unit 20 has a substantially double-pipe structure. The lower side of the inner cylinder 25 is opened, and an inlet 26 for introducing water into the valve box 21 is formed. However, the inner cylinder 25 is not necessarily provided below the valve box 21. The inner cylinder 25 may be provided in the middle of the valve box 21 in the axial direction, and the lower side of the inner cylinder 25 may be continuous with the inlet 26 of the valve box 21. Although the opening area of the inflow port 26 is not particularly limited, in this embodiment, it is set to 50% or more of the opening area of the discharge port 12 of the pump casing 13. The shape of the inflow port 26 is not limited at all. For example, the peripheral portion of the inflow port 26 may be rounded to smooth the flow of water flowing from the inflow port 26. The upper side of the inner cylinder 25 opens in the valve box 21 and forms an outlet 30. The upper side of the inner cylinder 25 has a shape that is cut obliquely, and the upper end surface of the inner cylinder 25 is inclined by a predetermined angle θ from the horizontal plane. The numerical value of the predetermined angle θ is not particularly limited, but is preferably 10 to 45 degrees, for example.

  In the following, for convenience of explanation, the higher one of the inner cylinder 25 is referred to as the front, and the lower one is referred to as the rear. As shown in FIG. 4, the right side is referred to as the right direction and the left side is referred to as the left direction from the rear to the front. As shown in FIG. 5, bolt holes 27 through which the bolts 16 are inserted are formed through the valve box 21 along the axial direction (longitudinal direction) of the valve box 21. The valve box 21 is made of synthetic resin. However, the material of the valve box 21 is not limited at all.

  As shown in FIG. 4, a plurality of pins 28 projecting upward are formed in a portion outside the inner cylinder 25 in the lower end portion inside the valve box 21. On the other hand, holes 29 are formed in the left and right sides of the support member 23 so as to fit the pins 28. In FIG. 4, only the left hole 29 of the support member 23 is shown, and the right hole 29 is hidden by the valve body 22, but actually the holes 29 are formed on both sides of the support member 23. Yes. The pins 28 are also provided at positions corresponding to the holes 29 (see FIG. 8). In the present embodiment, the support member 23 is made of synthetic resin. However, it is of course possible to form the support member 23 from another material (for example, metal).

  The valve body 22 is made of a substantially flat lid member. Here, the valve body 22 is formed in a substantially elliptical disk shape that is slightly larger than the outlet 30 of the inner cylinder 25. The upper end surface of the inner cylinder 25 is formed in a substantially elliptical annular shape so that the outlet 30 has a substantially circular shape in plan view. Therefore, the valve body 22 is formed in a substantially elliptic shape so as to cover the outflow port 30, and has a substantially circular shape in plan view when the outflow port 30 is closed.

  As shown in FIGS. 7A and 7B, the left and right corners of the upper surface of the valve element 22 are cut off linearly along the front-rear direction. That is, so-called chamfering is performed. As a result, the left and right sides of the upper surface of the valve body 22 are inclined surfaces 31 corresponding to the curved shape of the inner surface so as to match the inner surface of the valve box 21 when the valve body 22 is opened (see FIG. 8). Is formed. By chamfering the valve body 22 in this manner, it is possible to prevent the corners on the upper surface of the valve body 22 from colliding with the inner surface of the valve box 21 until the valve body 22 is sufficiently opened. The degree of opening increases. As shown in FIGS. 6 and 8, in this embodiment, the valve body 22 rotates to a position that is substantially parallel to the axial direction of the valve box 21. That is, the valve body 22 rotates to a position that is substantially parallel to the direction of water flow in the valve box 21. In other words, the inclined surface 31 of the valve body 22 is formed so that the valve body 22 is substantially parallel to the axial direction of the valve box 21 when opened.

  As shown in FIG. 4, a pair of left and right support pieces 32 extending rearward from the valve body 22 are integrally formed on the rear side of the upper surface of the valve body 22, and a rotating shaft 33 is interposed between the support pieces 32. It is laid over. The rotating shaft 33 is formed integrally with the support piece 32. When the support member 23 is attached to the valve box 21 so that the pin 28 of the valve box 21 is fitted in the hole 29 of the support member 23, as shown in FIGS. It is sandwiched between the box 21 and is rotatably supported. In this way, the valve element 22 is attached to the valve box 21 so as to be freely opened and closed. In the present embodiment, the support member 23 is joined to the valve box 21 by ultrasonic welding.

  As shown in FIG. 6, the valve body 22 is formed such that the center of gravity G of the valve body 22 is located on the front side of the rotation shaft 33, that is, on the center side of the inner cylinder 25. Therefore, in a state where the external force in the opening direction is not applied to the valve body 22, the valve body 22 rotates toward the inner cylinder 25 due to gravity and closes the inner cylinder 25. In the present embodiment, in the state in which the valve body 22 is opened, the length in the front-rear direction between the center of gravity G of the valve body 22 and the axis of the rotating shaft 33 is the same as the front surface (closed surface) of the valve body 22. It is about ½ of the length in the front-rear direction between the rear end of the rotating shaft 33.

  The material of the valve body 22 is not limited at all, and the valve body 22 may be formed of a synthetic resin or the like. In the present embodiment, the valve body 22 is made of synthetic rubber in order to improve the sealing performance. In addition, a metal plate is provided inside so as to increase the specific gravity of the valve body 22 and not to be greatly deformed even when back pressure is applied.

  In this embodiment, the rotation shaft 33 is provided on the valve body 22 side and the bearing of the rotation shaft 33 is provided on the support member 23 side. However, the rotation shaft is provided on the support member 23 side. A bearing may be provided on the valve body 22 side. The structure of the support mechanism that rotatably supports the valve body 22 is not limited at all.

  The upper lid 24 is inserted into the upper part of the valve box 21. In the present embodiment, the upper lid 24 is formed of a synthetic resin and is joined to the valve box 21 by ultrasonic welding. However, the material of the upper lid 24 and the joining method are not limited at all. The upper lid 24 prevents the valve body 22 from flowing out of the valve box 21 when the valve body 22 is detached from the valve box 21. As shown in FIG. 4, an opening 34 having substantially the same diameter as the inner cylinder 25 is formed at the center of the upper lid 24. The above is the configuration of the check valve unit 20.

  As described above, the check valve unit 20 is installed between the flange 15 and the companion flange 17 of the pump casing 13 and is directly connected to the pump casing 13. As shown in FIG. 1, a packing 36 made of rubber or the like is sandwiched between the flange 15 of the pump casing 13 and the check valve unit 20. A packing 37 made of rubber or the like is also sandwiched between the check valve unit 20 and the companion flange 17. A discharge pipe 35 is connected to the companion flange 17 via a valve socket 38. The valve socket 38 and the discharge pipe 35 are made of vinyl chloride. A spiral groove is provided in the outer peripheral surface of the lower portion of the valve socket 38 and the inner peripheral surface of the companion flange 17, and the lower portion of the valve socket 38 is screwed into the companion flange 17. The upper part of the valve socket 38 and the discharge pipe 35 are joined by an adhesive (see FIG. 9). However, the material and connection form of the valve socket 38 and the discharge pipe 35 are not limited to those described above, and other materials or connection forms may of course be employed.

  As shown in FIG. 2, the check valve unit 20 of this embodiment does not have a portion that protrudes to the side of the flange 15 and the companion flange 17. The side surface of the check valve unit 20 is substantially flush with the side surfaces of the flange 15 and the companion flange 17. Further, the check valve unit 20 does not have a portion protruding outward from the pump casing 13 in plan view. That is, the check valve unit 20 is located inside the outer edge of the pump casing 13 in plan view.

  During operation of the submersible pump 10, water is sucked from the suction port 11 (see FIG. 1) of the pump casing 13, and this water is pumped by an impeller (not shown) in the pump casing 13 and discharged from the discharge port 12. The The water discharged from the discharge port 12 flows into the check valve unit 20 and passes upward through the inner cylinder 25 of the check valve unit 20. At this time, an upward external force is applied to the valve body 22 by the momentum of water, and the valve body 22 rotates about the rotation shaft 33 as a fulcrum and takes a posture substantially parallel to the water flow direction (see FIG. 6). . As a result, the inner cylinder 25 is opened, and water flows from the inner cylinder 25 into the valve box 21 and then flows out of the valve box 21 through the opening 34. Thus, the water that has passed through the check valve unit 20 flows into the discharge pipe 35 and flows through the discharge pipe 35.

  On the other hand, when the operation of the submersible pump 10 is stopped, the valve body 22 does not receive an upward external force due to the flow of water, and thus rotates downward due to gravity, and the inner cylinder 25 is closed (see FIG. 5). . As a result, it is possible to prevent water from flowing downward through the discharge pipe 35, that is, backflow to the submersible pump 10.

  As described above, according to the pump unit 1 of the present embodiment, since the check valve unit 20 is directly connected to the pump casing 13, a pipe joint for connecting the check valve unit 20 and the pump casing 13 is used. Is unnecessary. Therefore, the number of parts can be reduced. In addition, the cost can be reduced by reducing the number of parts.

  Since the phase flange 17, the check valve unit 20, and the flange 15 of the pump casing 13 are fastened by the common bolt 16, the number of fasteners can be reduced as compared with the case where they are fastened separately. . Therefore, the number of parts can be further reduced. Further, the connection work of the check valve unit 20 is simplified.

  Since the valve body 22 of the check valve unit 20 is formed of a lid-like member and the valve body 22 is substantially parallel to the direction of water flow when opened, the pressure loss in the check valve unit 20 is reduced. Can be suppressed. Therefore, although the check valve unit 20 is downsized, the pumping performance of the submersible pump 10 is not significantly reduced.

  Since the inclined surface 31 that is in surface contact with the inner peripheral surface of the valve box 21 is chamfered with respect to the valve body 22, the valve body 22 at the time of opening is set in the flow direction without increasing the size of the valve box 21. It becomes possible to make it substantially parallel.

  Since the upper end surface of the inner cylinder 25 of the check valve unit 20 is inclined from the horizontal plane, the rotation angle of the valve body 22 during opening and closing can be reduced. Therefore, wear associated with opening and closing of the valve body 22 can be suppressed, and the life of the check valve unit 20 can be extended. As a result, the reliability of the check valve unit 20 can be improved.

  Since the check valve unit 20 is located on the inner side of the outer edge of the pump casing 13 in plan view, the check valve unit 20 does not protrude sideways. Therefore, space saving of the pump unit 1 can be achieved. Moreover, since there is no protruding part, the workability | operativity of the handling of the pump unit 1 improves.

  In the above embodiment, the companion flange 17, the valve box 21, and the flange 15 of the pump casing 13 are fixed by the bolts 16. Further, the valve socket 38 was fixed to the companion flange 17. However, regarding the mounting form of the valve box 21 and the like, various modifications are possible without being limited to the above-described form.

  For example, as shown in FIG. 10, the phase flange 17 and the valve socket 38 of the above embodiment may be integrated, and the valve box 21 may be bolted to the integrated phase flange 17a.

  Further, as the upper cover of the check valve unit 20, a valve socket 24a as shown in FIG. 11 may be used instead of the thin plate-shaped upper cover 24 (see FIG. 4). Thus, the upper flange of the valve box 21 also serves as a valve socket, so that the companion flange 17 can be omitted.

  In the above embodiment, the check valve unit 20 is simultaneously connected to the phase flange 17 and the flange 15 of the pump casing 13 by using the common bolt 16. However, it is of course possible to connect the check valve unit 20 to the companion flange 17 and the flange 15 separately. For example, as shown in FIG. 12, flanges 41 and 42 are provided at both upper and lower ends of the valve box 21, the valve box 21 and the flange 15 of the pump casing 13 are fastened with screws 44, and the valve box 21 and the companion flange 17 are connected. You may make it fasten with the screw | thread 43. FIG. However, in such a form, the internal space of the valve box 21 is reduced by the provision of the flanges 41 and 42. That is, since the hexagonal portions of the screws 43 and 44 are located on the side of the valve box 21, the valve box 21 must be narrowed inward by that amount. Conversely, in the above embodiment, the hexagonal portion of the bolt 16 is located on the side of the companion flange 17, and the valve box 21 is not dimensionally restricted by the hexagonal portion of the bolt 16. It can be secured greatly. Therefore, pressure loss can be further reduced.

<Embodiment 2>
The pump unit 1 according to the second embodiment shown in FIG. 16 is a modification of the check valve unit 20 according to the first embodiment. As shown in FIGS. 13 to 15, the check valve unit 20 according to the second embodiment has not only a backflow prevention function for preventing backflow to the submersible pump 10 but also an air vent that discharges air accumulated on the discharge side of the submersible pump 10. It also demonstrates its function.

  In general, in the submersible pump 10, if air accumulates on the discharge side of the submersible pump 10 (that is, the inside of the pump casing 13 or the discharge pipe 35), water may not be smoothly discharged. is there. Therefore, it is preferable to provide an air vent passage for discharging the air accumulated on the discharge side of the submersible pump 10. However, if an air vent passage is simply formed on the discharge side of the pump, part of the discharged water will flow out of the air vent passage during pump operation. Therefore, when providing the air vent passage, it is necessary to provide an air vent valve that discharges air but prevents the outflow of water. The check valve unit 20 of the present embodiment is obtained by providing an air vent passage and an air vent valve in the check valve unit of the first embodiment.

  As shown in FIG. 13, in this embodiment, an auxiliary casing 50 that protrudes laterally is formed on the side of the valve box 21. The auxiliary casing 50 protrudes in an oblique direction from the front-rear direction of the valve box 21 (left-right direction in FIG. 13). The auxiliary casing 50 is formed integrally with the valve box 21 and is therefore formed of the same synthetic resin as the valve box 21.

  As shown in FIG. 14, the outer end of the auxiliary casing 50 is opened to form an air discharge port 51. An air vent hole 52 is formed through the side wall of the inner cylinder 25. As a result, an air vent passage 54 that communicates the inside of the inner cylinder 25 and the outside of the valve box 21 is defined in the auxiliary casing 50. A ball-shaped valve element 53 larger than both the air vent hole 52 and the air discharge port 51 is movably inserted into the air vent passage 54.

  As shown in FIG. 15, when the discharge water flows into the inner cylinder 25, the valve body 53 is pushed into the air discharge port 51 side by the pressure of the discharge water, and closes the air discharge port 51. As a result, the discharge water is prevented from flowing out. On the other hand, when the discharge water does not flow in the inner cylinder 25, it stays below the air vent passage 54 due to its own weight and opens the air outlet 51. As a result, the air in the inner cylinder 25 is discharged from the air discharge port 51. In order to exhibit such an action, the valve body 53 is formed of a material having a predetermined specific gravity. However, the material itself of the valve body 53 is not limited, and for example, synthetic resin, rubber, metal, or the like can be suitably used.

  In addition, the pump unit 1 of this embodiment can be used for conveyance of sewage. However, in many cases, various kinds of filth are mixed in the sewage. Therefore, when the pump unit 1 is used for conveying sewage, the air vent hole 52 and the air discharge port 51 are preferably formed relatively large. For example, it is preferable to form the air vent hole 52 and the air discharge port 51 with respect to the valve box 21 and the inner cylinder 25 at the dimensional ratios shown in FIGS.

  As shown in FIG. 16, the check valve unit 20 is arranged so that the auxiliary casing 50 protrudes toward the submersible pump 10. Therefore, the auxiliary casing 50 does not protrude to the side when viewed as a whole of the pump unit 1. The auxiliary casing 50 is located inside the outer edge of the pump casing 13 in plan view.

  As described above, according to the present embodiment, in the check valve unit 20, not only the back flow to the submersible pump 10 can be prevented, but also the retention of air on the discharge side of the submersible pump 10 can be prevented. . Therefore, in addition to the effects of the first embodiment, it is not necessary to separately provide an air vent valve, so that the number of parts can be further reduced. Moreover, according to this embodiment, it is not necessary to connect an air vent valve separately, such as connecting a separate air vent valve to the discharge piping 35. Therefore, the assembly operation of the pump unit 1 can be further simplified.

  Although the auxiliary casing 50 protrudes from the valve box 21, the auxiliary casing 50 is disposed so as to protrude toward the submersible pump 10, so that the pump unit 1 as a whole has no portion protruding sideways. Therefore, space saving of the pump unit 1 can be achieved. Moreover, the handleability of the pump unit 1 can be improved.

<Other embodiments>
In each of the above embodiments, the check valve unit 20 is directly connected to the pump casing 13. However, as long as the check valve unit 20 is disposed beside the submersible pump 10, that is, the height of the check valve unit 20. As long as the position is below the uppermost end of the submersible pump 10, a pipe joint or the like may be interposed between the check valve unit 20 and the pump casing 13. Even in such a case, since the distance between the check valve unit 20 and the pump casing 13 is short, a long pipe joint is not necessary.

  In addition, the installation place of the pump unit 1 which concerns on this invention is not limited at all. Moreover, the fluid conveyed by the pump unit 1 is not limited to water. For example, a plurality of pump units 1 according to the above embodiments may be installed in a sewage treatment facility, and sewage may be conveyed by the pump units 1.

  As described above, the present invention is useful for a pump unit including a backflow prevention device.

3 is a side view of the pump unit according to Embodiment 1. FIG. 3 is a plan view of the pump unit according to Embodiment 1. FIG. It is a side view of a pump. 2 is an exploded perspective view of a check valve unit according to Embodiment 1. FIG. It is a longitudinal cross-sectional view of the check valve unit according to the first embodiment. It is a longitudinal cross-sectional view of the check valve unit according to the first embodiment. (A) is a top view of a valve body, (b) is a side view of a valve body. It is a top view of the state which removed the upper cover of the non-return valve unit. It is a longitudinal cross-sectional view which shows the connection form of a non-return valve unit. 6 is a longitudinal sectional view showing a connection form of a modified example of Embodiment 1. FIG. FIG. 6 is a longitudinal sectional view showing a connection form of another modification of the first embodiment. FIG. 6 is a longitudinal sectional view showing a connection form of another modification of the first embodiment. FIG. 6 is a plan view of a state where an upper cover of a check valve unit according to Embodiment 2 is removed. It is AA sectional view taken on the line of FIG. FIG. 15 is a view corresponding to FIG. 14 with the valve body opened. 6 is a plan view of a pump unit according to Embodiment 2. FIG. It is a side view of the conventional pump unit.

Explanation of symbols

1 Pump Unit 10 Pump 11 Suction Port 12 Discharge Port 13 Pump Casing 15 Flange 16 Bolt 17 Phase Flange 20 Check Valve Unit (Backflow Prevention Device)
21 Valve box (valve casing)
DESCRIPTION OF SYMBOLS 22 Valve body 23 Support member 25 Inner cylinder 26 Inlet 30 Outlet 33 Rotating shaft 35 Discharge piping 50 Auxiliary casing 51 Air exhaust port 52 Air vent hole 53 Valve element 54 Air vent passage

Claims (7)

A pump unit comprising a pump having a pump casing in which a suction port and a discharge port are formed, and a backflow prevention device for preventing backflow to the pump,
The backflow prevention device is
A substantially cylindrical valve casing having an inlet formed at one end and an outlet formed at the other end;
A valve body made of a lid-like member that covers the flow path of the valve casing in the valve casing so as to be freely opened and closed;
The valve body is opened and closed between an open state in which the valve body is in a posture substantially parallel to the axial direction of the valve casing and a closed state in which the valve body is in a posture orthogonal to or oblique to the axial direction of the valve casing. A support mechanism that freely supports the shaft,
A pump unit comprising a backflow prevention device, which is disposed on a side of the pump at a height position equal to or lower than an uppermost end portion of the pump.   The pump unit provided with the backflow prevention device according to claim 1, wherein the valve casing is located inside an outer edge of the pump casing in a plan view.   The pump unit provided with the backflow prevention device according to claim 1 or 2, wherein the valve casing is directly connected to the pump casing. Around the outlet of the pump casing, a flange formed with a bolt hole is provided,
The pump has a companion flange that is designed to be bolted to the flange with a bolt hole formed therein and to which a discharge pipe is connected;
The said backflow prevention apparatus is installed between the said flange and the flange of the said pump casing by fastening the said flange, the said valve casing, and the flange of the said pump casing with the common volt | bolt. The pump unit provided with the backflow prevention apparatus as described in any one of -3. Inside the valve casing is provided with a substantially cylindrical inner cylinder having one end forming the inlet or continuing to the inlet and the other end opening in the valve casing.
The valve body covers the other end side of the inner cylinder so as to be freely opened and closed,
The said valve casing is provided with the air vent path which connects the exterior of the said valve casing and the inside of the said inner cylinder, and the air vent valve which opens and closes the said air vent path. A pump unit comprising the described backflow prevention device. An air vent hole is formed through the side wall of the inner cylinder,
The valve casing is provided with an auxiliary casing that protrudes to the side of the valve casing and has an air outlet that is open to the outside and that defines the air vent passage,
The air vent valve is movably provided in the auxiliary casing, and closes the air discharge port when fluid flows in the inner cylinder, and opens the air discharge port when fluid does not flow in the inner cylinder. The pump unit provided with the backflow prevention apparatus of Claim 5 provided with the valve body of this. The pump unit provided with the backflow prevention device according to claim 6, wherein the auxiliary casing protrudes toward the pump and is located on an inner side than an outer edge of the pump casing in a plan view.

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